Automatic fuel regulator for internal combustion engines



1933- c. 1... STOKES 1,920,487

AUTOMATIC FUEL REGULATOR FOR INTERNAL COMBUSTION ENGINES Filed May 19, 1927 is journalled in suitable bosses on the extension of.

Patented Aug. 1, 1933 AUTOMATIC FUEL REGULATOR FOR INTERNAL COMBUSTION ENGINES Charles L. Stokes,.Los Angeles, Calif., assignor,

by mesne assignments, to Evanston, 111., and Clifford C.

coe, 111., Trustees Lynn A. Williams,

Bradbury, Glen- Application May 19, 1927. Serial No. 192,581 12 Claims. (01123-119) My invention relates to improvements in automatic fuel regulators for internal combustion engines.

The principal object of my invention is to provide simplified structures wherein the vacuum induced by the pistons of an internal combustion engine is primarily utilized for supplying and controlling a priming charge for starting the engine and thereafter the priming charge is varied in accordance with varying temperatures of part of the engine.

Referring to the drawing, in which the same numbers indicate like parts:

Fig. 1 is a side view of an internal combustion engine having my invention attached thereto on a carburetor;

Fig. 2 is a vertical cross section of the air entry of the carburetor;

Fig. 3 is a cross section of a thermostatic spring attached to the air entry;

Fig. 4 is a cross section along the Fig. 3;

Figs. 5 and 6 show an alternative construction for Figs. 1 and 1.

An internal combustion engine 10 may be of the well known four cycle type, having an exhaust pipe 11 and an intake manifold 12. A carburetor 13, of any well known type, is attached to manifold 12 and has a fuel nozzle 14, an air entry 15 and a float chamber 16 for feeding liquid fuel to nozzle 14. Air through air entry, or air horn 15 is mixed with liquid fuel from nozzle 14 and supplied to engine 10, responsive to the suction thereof, and the volume of the air find fuel mixture is regulated by the usual thro tle valve 17.

Inasmuch as the particular structure of the carburetor 13 for mixing air and fuel, excepting at starting and warming up periods, forms no part of my invention, detailed descriptions of the same are deemed unnecessary because my invention is applicable to any suction feed carburetor, but a particular type, known' as the plain tube type, is illustrated, wherein substantially all the air is introduced through the main air entry 15, except the air entry for idling (not shown).

Air buretor 13 or, as is generally preferred for as-i sembly, is made separate and attached to the carburetorbody'by bolts or in any other convenient manner in order to provide anair-tight joint therebetween, and air horn 15 is generally cylindrical in bore containing achoker valve 18, mounted oif center on a spindle 19. Spindle 19 line M; of

air horn 15, one of which, boss 20, being enclosed horn 15 may be an integral part of car-\- by a cap 21 which also encloses substantially airtight one end of spindle 19. Boss 20 has an extension 22 to which is attached one end of a bimetallic thermostatic spring 23. the other end of spring 23 being held in a slot cut in the enclosed end of spindle 19. Spring 23 is adjustably held in a slot in extension 22 by a set screw 24, a slot being cut in cap 21 to accommodate the shank of screw 24.

Spring 23 is preferably of spiral cross section and is of the proper width and thickness to perform the functions to be hereinafter described, and a variation of its functions under similar conditions of engine operation may be had by moving its one end detachably held in extension 22.

A pipe 25 conveys heated exhaust gases from the interior of pipe 11 to the interior of cap 21, for conveying heat to spring 23, a discharge pipe 26 serving to pass the exhaust gases from cap 21 to atmosphere or otherwise.

Alternatively, as shown in Figs. 5 and 6, a hot air stove 2'7 surrounds exhaust pipe 11 and heated air is drawn therefrom through pipe 25, cap 21 and passage 28 to the interior of air horn 15 on the atmosphere side of choker valve 18 responsive to the engine suction, it being noted in this case that pipe 26 is eliminated and its place of entry is drawn into the cylinders of engine 10 and fired,

a sudden increase in vacuum occurs due to increased piston speed, the idling speed being greater than the cranking speed, as is explained in my Patents, No. 1,694,801, Dec. 11, 1928, No. 1,799,486, April 7, 1931, No. 1,750,766, Mar. 18, 1930, No. 1,764,659, June 17, 1930. and others.

This increase in vacuum causes a greater or less degree of opening of choker valve 18, due to the difference in pressures applied to'the two segments thereof, against the resistance of thermostatic spring 23, permitting .the entry of a greater amount of air and thus reducing the suction on nozzle 14, to the end that the proportion of air to fuel is increased whereby a rich idling mixture is obtained.

Thereafter, with increasing engine tempera tures, increasingly heated exhaust gases are applied through pipe 25 to spring 23 whereby, when optimum engine operating temperatures are reached, choker valve '18 will be opened a sufficient amount to cause the cessation of flow of rich priming charges from nozzle 14. Likewise, after the first priming charge is fired and throttle 17 is opened beyond idling position, the restriction to opening choker valve 18 .by spring 23 will cause a corresponding and proportionate rich fuel supply from nozzle 14 for increased engine speed, until the increased heat from the exhaust gases causes sufilcient expansion of spring 23 to open valve 18 to normal position for that increased speed.

Again, when throttle 17 is suddenly opened wide for acceleration, a high suction is placed on nozzle 14 to provide an accelerating charge and thereafter the combined effects of suction and heat permit choker valve 18 to open wide where'- by maximum volumetric capacity is obtained.

In this manner a simple attachable and detachable automatic fuel regulator is obtained for carburetors whereby easy starting and running is had for any temperatures and the cost ismade a minimum.

The alternative constructions shown in Figs. 5 and 6 provide that the engine suction applied through passage 28 cap 21 and pipe 25, after the first priming charge is fired, induces a draft of heated air therethrough from stove 27 whereby thermostatic spring 23-varies its position in accordance with engine temperatures and varies the to said thermo-responsive element.

position of choker valve 18.

I claim as my invention:

1. The-combination with an internal combustion engine having an exhaust passage, of a carburetor having an air entry, a valve spindle in the air entry, a valve mounted on the spindle, a thermoresponsive element adapted to control said valve, a spring on one end of the spindle and a conduit leading from the exhaust passage 2. In an automatic fuel regulator for internal combustion engines, the combination with an internal combustion engine having an intake manifold and an exhaust passage, of a carburetor having a single air entry, an off center valve normally closing the air entry, said carburetor having a fuel nozzle leading to the manifold, a throttle valve in the connection of the carburetor with the manifold-between the nozzle and the manifold, a spindle for the off center valve extending through the wall of the air entry, a

thermostatic spring connected to the spindle at one end and to an extension of the wall at the other normally closing the off center valve, a

cap mountedon the wall 'and enclosing the spindle end and spring, and a pipe leading from.

the exhaust passage to the interior of the cap for subjecting the spring to the heat of the exhaust, the chamber of the cap having an opening leading therefrom.

3. The combination with an internal combustion engine having an exhaust passage, of a carburetor having a single air entry, an eccentrically supported air valve normally closing said air entry, a shaft supporting said valve extending through the wall of the air entry, 9. thermostatic spring anchored to the shaft at its one end and to an extension of the wall at its other end for normally closing the eccentrically supported valve, a cover cap mounted on the wall I and. enclosing said spring and the shaft end, a pipe leading from the exhaust passage to the cap for conducting heat from the exhaust passage to the interior of the same for subjecting the spring to the heat and an opening in the cap and leading therefrom.

4. The combination with an internal combustion engine having an exhaust passage, of a carburetor having a single air entry, an eccentrically supported air valve normally closing the said air entry, a shaft supporting said valve extending through the wall of the said air entry, a thermostatic spring anchored to the shaft at its one end and to a laterally extending member of the wall at its other end for normally closing the eccentrically supported valve, a cover cap secured to said member for enclosing said thermostatic spring and the shaft end, a pipe leading from the said exhaust passage to the interior of the cap for subjecting the spring to the heatof the exhaust and an opening in the cap and leading therefrom.

5. The combination with aninternal combustion engine having an exhaust passage, of a carburetor having a single main air entry, an eccentrically supported air valve normally closing-said air entry, a spindle supporting said valve having its one end extending through the wall of the air entry, a thermostatic spring having its one end anchored to the extending portion of the spindle and adjustably secured at its other end to a laterally extending member of the wall to normally close the said eccentrically supported valve, a cover cap mounted on the said member enclosing the thermostatic spring and the spindle end, a pipe leading from the exhaust passage to the. interior of the cap for conducting heat from the exhaust passage to the interior of the cap to subject said spring to the heat of the exhaust and an opening in the cap and leading therefrom.

6. In an internal combustion engine including suction means wherein the suction is substantially increased upon ignition of the engine, a carburetor having a chambertherein for mixing fuel and air and having an air inlet thereto, a choke valve. having a closed position substantially totally restricting the flow of all the air passing to said chamber while starting the-engine when cold, said choke valve being movable from its closed position to a partially open position in said air inlet by said suction means upon ignition of starting the engine when warm, and means whereby the amount of the initial opening of said choke valve may be adjusted to secure the proper amount of air fiowto said mixing chamber with varying atmospheric temperature.

- I '7. In an internal combustion engine including suction means wherein the suction is substantially increased upon ignition of the engine, a carburetor having a chamber therein for mixing fuel and air and having an air inlet thereto, a choke valve having a closed position during the starting of the engine substantially totally restricting the flow of all the air passing to said strength to hold said choke valve in some parchamber, said choke valve being-movable from its closed position to a partially open position in said air, inlet by said suction means upon ignition of the engine, a thermostatic spring element responsive to engine heat operatively connected to said choke valve, said thermostatic spring element being mounted externally of said air inlet and having sufficient strength normally to hold said choke valve in said partially open position until said engine is warmed up and having sufficient strength to hold said choke valve in some open position depending upon engine temperature upon starting the engine when warm.

8. In an internal combustion engine including suction means wherein the suction is increased upon ignition of the engine, a carburetor having a mixing chamber and having an air inlet communicating'therewith and with said manifold, a choke valve in said air inlet having a closed position, and a partially open position and an open position for controlling the flow of substantially all the air passing to said mixing chamber, said choke valve being movable from said closed position to said partially open position by said suction means upon ignition of the engine, and a combined thermostat and spring outside of said air inlet responsive to engine heat and yieldable to permit the increased suction action upon ignition of the engine to move said choke valve to said partially open position and having sufficient strength to hold said choke valve in said partially open position thereafter until influenced by the heat of the engine, said combined thermostat and spring being operatively connected to said choke valve.

9. In an internal combustion engine, in combination, a carburetor, having a chamber for mixing fuel and air and having an air inlet to said mixing chamber, an offset choke valve positioned in said air inlet for controlling the flow of substantially the total volume of air passing to said mixing chamber, said choke valve having a substantially closed position while starting the engine when cold and partially opening to allow an increase in air flow to said mixing chamber upon increased suction occasioned by ignition of the engine, a thermostatic spring element responsive to the heat of the engine, connections between said thermostatic spring element and said offset choke valve, mounting means for positioning said thermostatic spring element external: ly of said air inlet, said thermostatic spring element serving to control the position of said choke valve in saidair entryway substantially in accordance with the-heat conditions of the engine and said thermostatic spring element having suflicient tially open position it the engine is started when warm.

. 10. In an internal combustion engine, a car-' buretor having an air entryway, means for controlling and substantially totally restricting the flow of air to said carburetor comprising a choke valve positioned in said air entryway and normally closing same when the engine is cold, differential pressure means for initially opening said choke valve during a starting operation when ignition of the engine occurs, thermostatic spring means responsive to engine heat for controlling the movement of said choke valve, said thermostatic spring means being placed externally of said air entryway and out of contact with the air flowing therethrough, and said thermostatic spring means having suflicient strength resiliently to retain said choke valve in some partially open position upon starting the engine when warm.

11. In an internal combustion engine, a carburetor having an air inlet, an offset choke valve in said air inlet, said offset choke valve having. a closed position and a partially open position, said offset choke valve when in said closed position substantially totally restricting the flow of air to said carburetor, differential pressure means for normally initially opening said offset choke 'valve upon ignition of the engine, thermostatic spring means responsive to engine heat positioned externally of said air inlet for controlling ing suction means wherein' the suction is increased upon ignition of the engine, a carburetor having a mixing chamber and having an air inlet providing communication with said chamber and said suction means, a choke valve having a closed position substantially totally restricting the flow of air to said chamber, said choke valve being movable from its closed position to a partially open position in the air inlet by said suction means upon ignition of the engine, and means outside. of said air inlet for holding said choke valve in a partially open position during the starting of the engine when warm.

CHARLES L. STOKES. 

